Grinding machine



Oct. A8, 1929. w. J. BAUMBERGER GRINDING MACHINE 6 Sheets-Sheet FiledNov. 5, 1925 IN veA/rox ...11am n C- 8, 1929 w. J. BAUMBERGER 1,730,838

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W. J. BAUMBERG ER l ERINDING MACHINE Filed Nov. 5, 1925 6 Sheets-Sheet 6Patented Oct. 8, 1929 UNITED STATES PATENT OFFICE WILLIAM J'.BAUMBERGER, OF DAVENPORT, IOWA, ASSIGNOR TO MICRO MACHINE COMPANY, OFBETTENDORF, IOVJA, A CORPORATION F IOWA GRINDING MACHINE Applicationfiled November 5, 1925. Serial No. 67,175.

This in\f'ention relates to grinding machines having a plurality ofgrinding wheels, and more particularly to internal grinders in whichgrinding wheel spindles are rotated simultaneously about their axes andalso in an orbital path about other axes eccentric to the spindles.

lflfith machines in which a single grinding wheel is employed to tinisha bore in work which must be ground trom opposite directions, andespecially when the bore is of two diameters and arranged in axialalignment, either the work must be set up upon the machine for eachOperation, or the fixture must be adjustable so that opposite ends ofthe work can be positionedI adjacent the wheel. A similar condition ispresent when a single grinding wheel is employed to finish Iwork whichis lormed in separate sections to be assembled or related with theirfinished bores in axial alignment. Considerable time is thereforeconsumed to accurately position the work, so that the bores to beinished will be presented in the same manner to a tool, and the same istrue either when the work is set up for each grinding operation or whenthe work carrier must be adjusted. Additional time is also required,when a single grinding wheel is used to grind bores ot differentdiameters, as the wheel must be changed between the operations.

An object ot' my invention is to provide a grinding machine in whichthere is a pair ot grinding wheels intermediate which work can besecured and reciprocated so that bores in two pieces ot work, or a borewhich is to be ground from opposite directions in an assembled piece ofwork, can be finished while the work is maintained in a definite lixedposition upon a table.

A further object ot my invention is to provide a grinding machine inwhich a reciprocating Work table and a pair oit.' grinding wheels can beautomatically operated by meclmnismy in definite relations of movement.

Another object of my invention is to provide a grinding machine in whicha reciprocating work table and a pair of grinding wheels can be operatedfrom a single source ot motive power, by mechanisms which can themachine taken Online 5 be selectively operated to cause the table tomove ina deiinite speed relation withr that et the grinding wheels, orto be moved independently ot the speed ot' the rotation oi the grindingwheels. l

Still another object of my invention resides in providing mechanism forreciprocating a work table between a pair of grinding wheels which canbe operated either by power driven mechanism, or through the same n1chanism from adjacent either wheel by manually operated mechanism.

lVit-h the above and other objects in view the invention' may be said tocomprise the machine as illustrated in the accompanying drawingshereinafter described and particularly set forth in the appended claims,or such 'modifications thereof as will be obvious to those skilled inthe art to which the invention appertains. It is, therefore, to beunderstood that while the following description and accompanyingdrawings set forth in detail certain means embodying the invention, thedisclosed means constitutes but one ot' the various mechanical forms inwhich the principle oit' the invention may be employed.

Reference should be had to the accompanying drawings, forming a part otthis specilication in which:

Figure l is a -iront elevation of a grinding machine embodying theinvention.

Figure 2 yis a rear elevation of the machine, the work carrying iixture,grinding wheell spindles and associated parts, and the mot-or plant notbeing illustrated as in F igure l.

Figure 3 is an elevational view, partially in section illustrating thepower transmitting plant and the movement of one of the grinder wheels.f

Figure 4t is a vertical sectional view taken longitudinally ot themachine and illustrating the `main drive shaft and the mechanism forreciprocating the work carrying bed.

Figure 5 is a horizontal sectional view of i 5 of Figure 4: showing aportion of the drivingmechanism.

Figure G is a vertical sectional view taken transversely ot onek end ofthe machine on line of igure 5 illustrating the driving mechanism.

Figur 7 is a horizontal sectional vieiv ot a portion of the machine,taken on line 7 7 o' Figure il, illustrating the mechanism forreciproeati 1g the vvorl; carrying bed.

Figure 8 is a vertical section of a portion et the machine talren online 8-8 ot Figure l, ard illustrating the mechanism for controlling andoperating the Work carrying bed.

Figure 9 is a horizontal se tional View taken on line 9 9 ot Figure 1,illustrating one of the hand operated Wheels and mechanism operatedthereby for reciprocating the Worlr car ying bed.

Referring to the accompanying dre-.Wings by characters of reference, themachine consists of a supporting base A Which has at the og there-ol abed B upon each end ot' which pindle carrying heads C are rigidlysecured. A lixture, or Werl; holder F is mounted upon theV table (ilwhich driven by power, or is n'iovajble by hand, to reciprocateintermediate the spindle carrying heads on the bed. The specilicstructure of the Work holder does not concern the present invention, itbeing` suficient for the present disclosure that this Work holder isadapted to be adjusted to rigidly sujip'ort Work, or sections ot Work,to be ground in alignment with the axes about which the spindles arebodily rotated. rl`he Work holder, beingl mounted on the table G, ismoved longitudinally ot the machine with the table, by a rack 10attached to the table which is driven by 'the pinion 11, as illustrateein Figure si. rllhe pinion 11 is driven in either direction thr ugh'thechange speed gears in the casing E which in turn are controlled by thein the reverse gear b X 7S 7 The automatic reversal of the table iscontrolled by adjustable stops in any conventional manner si itable forthis type of machine. ln addition to a. power drive, the table may beoperated by either one or a pair ot hand Wheels 16 as will appear morefully hereinutter.

'lhe specific manner ot mounting` and driving the spindles Within thespindle housings. shown in the drawings, and reference LOC 4 ma e had tothe pending applica` ion ior Ser. No. 723 ,626 tiled Aug. 7, 192e, as asie-citic manner ot constructing the same, it being understood that bothspindles are mounted in a sin'iilar manner, are rotated by similarmechanisms, and can be aligned,y or olilset iu parallel relationzwially. The spindles Within the spindle housings 1T are carried by andproject 'from the heads C, and are rotated simultaneouslj,7 about theirown airis and bodily in an orbital path about their oivn axis: Thespindles Within the housings 1T are cach provided with a grinding Wheel18, on their projecting end, and the ases of the spindles in thisdisclosure are ar anged in longitudinal alignment, TWherever desired as1for special Work the axis ,t the spindles may be in dilierent parallelplanes,

Power transmitting mechanism, which l Will nonv describe, is arranged torotate the spindles about their A motor 19 (Figs. l and may beconveniently located below the machine, and power is delivered there-`from by a belt 2O which extends around the motor pulley Wheel 21 andthe pulley Wheel 22 on the main drive shaft- The main drive sha'ltentends longitudinally Tvithin the machine trame and is formed ot acentral section 23 (Figs. 1 and intermediate sections 2 which can Lecoimecte-l or disconnected to the central section 28 1 and el) byintermediate clutches and sections 26 which i n w coimected vvitl "heshafts 2f which entent1 t l hrough bearings 2 in ends inach'ne frame andcarry 3 on the protruding ends thereon 2C ci the drive shaft areconnect/ee with the intcrmediate sections 2l. and ie shafts 2T byuniversal jolnts 30. Bearii 31 are pro vid ed to supi 'nt the intermediLe tions 2 oft the drive shalt, and similar bear ngs are prov ed tosupport the central section of the drive sli-att. Levers 32, extendingexternally ol: the macaine frame, are connected by link mechanisms 32Awith the clutches so thatv the operator can selectively connect ordisconnect the shafts 2 Prom the driven central shaft section 2. Thegrinder spindles Within the. housings 1T extend beyond the ends of thehead easings and a pulley 82 is secured upon yach ot the projectingends. fr belt extends u end the machine, transmitting power from themaii drive shalt to rotate the spindles L ,1.1 I f. v

their aires.

' antcgraph .iechanisms 15st (Fig. 1)

ribed in the said copendmg application "T fr N Y berial iso. 730.connect the bear ngs :.8

ully

1 and el) mechanically to the outer end grlinding vvhee spindles in sucha Way spindles may follow t ieir orbital vement freely While maintainingthe pr per belt tension to transmit power from the pulleys 29 to pulleys32, The universal oints SO alloiv the pulleys 29 to follow the movementsol the pantograph mechanisms. Counterweights 151 on levers 152 areassociated With pivots 153 and serve to countcrbalance the Weight ot'the pantograpli mechanisms 154i-, the levers 152 being attached at theirouter ends to projections from the bearings 2S.

The mechanism for rotating the spindles in an orbital path about theiraxes, referred o as being shown in the copending application, is drivenfrom the main drive shaft by the mechanism which l will now descrioe. Acounter shait Sil (Figs. 2 and 5) is secured eiteriorly of the rear sideor" the machine in bearing brackets 85 and carries a pulley 3T. A belt3S extends around the pulley 37 and a pulley o9 'which is secured uponthe central around the pullevs 29 and 32 at each Cil section 23 ot thedriven shaft. `A shaft l0 extends the full length of the machine trame,parallel with the counter shalt Sel and is rotatably mounted in thelearing brackets al and A pair of reversely arranged cone pulleys 43 andle are arranged intermediate the bearings 36 and el, the pulleys beingthe same size and located one above the other with their axes andsurfaces parallel and their peripheries sliolitly spaced. The conepulley 4tlis secured to the shaft l0 andthe cone pulley i3 carried by ashaft Zl5 which is mounted in the bearing brackets 36. Une end of theshaft 45 projects through the bearing 86 and a gear i6 is fixed theretoand arranged to mesh with a gear i7 secured to the counter shatt- 34.The cone pulley i8 will be rotated through its connections with theshafts 3d and l5 which are driven from the main drive sliait't. A geard8 is secured to the shaft d0, adjacent the cone pulley secured thereto,and meshes with a gear i9 which is mounted upon the stub shaft 50. Thisstub shaft 50 is rotatably mounted in the bearing bracket Lll andcarries a pulley l around which the belt 52 extends. The other en d oithe shaft is also provided with a gear 58 which meshes with a gear 5l,on a stub shalt 55. This shaft carries a pulley around which the belt 56extends. The belts and 56 ex tend into the grinder heads to rot-atemecha nism for causing orbital movement of the grinder spindlessimultaneously with the rotation about their axes above referred to. Thelower cone pulley, and consequently the shaft d0, is l'rictionallydriven from the upper cone pulley by means of a belt 57 which encirelesthe lower cone pulley and is adjust.- able longitudinally of the pulleysto give he desired speed ratio betweeuthe two.

For shitting the belt 57 (Fig. 2), there is a yoke 58 straddling thebelt and slidable along an inclined guide rod 59 parallel to thecontiguous peripheral portions oi the conical surfaces of the cones. Theyohe 58 is connected to the ends oil a cable which runs over a pulley orsheave (il adjacent one end ot the cone j iulleys and has its upper andlower runs parallel to the guide rod 59. Adjacent one end olf the base,the cable 6() is guided by pulleys (l2 und G3 trom which they travelover iliulleys (la and (l5 carried at one end of a rod 66. The cableextends ifrom the pulleys (Sil and (l5 around a rotary indicator plate(37, and a guide pulley G8 is provided to maintain the pu Vey undertension. The indicator 67 is mounted upon a rotatable shaft 69 carryinga drum to which both ends oi the cable are secured and by rotating suchshaft the yoke 58 will be moved .to shift the belt 57 to connect thecone pulleys so that the lower cone pulley will be driven at a desiredspeed relative to that at which the upper cone pulley is driven. In thismanner the speed of rotation of the tool can be regulated as desired.

'As the work is stationary in internal grinding and the spindles revolvein order to carry the wheel around the wall in the work to be ground,this latter movement is actually the worlr travel, and it is necessarythat the rate of speed of the orbital movement of the spindles bevariable. In order to remove a maximum amount ot stock and to eliminatewheel breakdown or wheel glazing, it is necessary to maintain a correctrelation between the wheel surface speed and the work travel. Byshitting the belt 57 longitudinally of the cones, the cone da will bedriven at different speeds from the cone i3 which is driven at aconstant speed from the motor, and theretore as the spindles are rotatedby the cone lei a desirable speed of orbital rotation can be obtained.

Y hen the movement of the work is regul u ted independently of thebodily rotation of the grinders itis diilicult to obtain the desiredrelation ot movement, and I thereiore provide mechanism whereby the workis reciproeated automatically from the driven cone 44, sothat there is aconstant ratio between the movement of the work and the orbital rotationet the grinders. The variable speed cone lill drives tue spindles in anorbital path anil also drives the work table, thus keeping a properrelation between the table travel and the revolutions per minute ot' therorbital movement of the spindles. rlhis direct driv-y ing relationsimplilies the operators problem. .For example, should the table be setto advance .O inch per revolution of the orbital rotation ot thespindles, it will continue yto advance .O50 inch per revolution et thespin dles in an orbital path, even though the rotation oi the spindlesbe increased or diminished in speed. The maintenance oit this relationutilizes the tull capacity of the grinding wheels without thepossibility of overtaxing them.

A pulley 70 is secured to the shaft 4l() which is driven from the cone44 and a belt 7l (Figs. l and 5) passes around the pulley 70 and apulley 72 carried by the countershaft 73 mounted in bearings 74 withinthe machine frame. A pulley 75 is mounted on the end ot thecounter-shaft 7 3, spaced from the belt 71, and a belt 76 extends aroundsuch pulley and a pulley 77 (FigsQl and 7) carried on one end ot ashaltwhich projects from the reverse gear box 78 located at the front. of themachine.

Power transmitted from the pulley 77 0perates the gearing within the box78 by means of which the pinion l1 is rotated and through its engagementwith the rack l0 the work carrying table G is reciprocated. A reversinggear mechanism 79 ot' the usual bevel gear and intermediate clutch typeis located within the box 7 8, which drives a stub shaft 80, extendinginto the casing be neath the bed. The inner end of the stub shaftcarries a bevel gear 81 which meshes .vith a bevel 32 on a countershaft83 Which arr-ies a spur pinion 31 meshn with a larger gear 35 S). i1series of Ej on a countershaft 86 (Fig. gears 87 are carried by theshaft and they of a gradually decreasing size tovrard the forward end ofthe shaft. rhe gears 37 mesh with gears 33 loosely mounted on a'parallelshaft 39, the gears 83 varying in size in reverse order as is common inspeed changing gearing. The shaft 39 iS hollow and slidable th rein is akey rod 90 carrying a hey 91 Which extends through a slot in the shaft89, and is adapted to engage with any one of the gears 8S to lrey it tothe shaft. Between each of the gears 83 there is a neutral spaceprovided by Washers 93 in -which the key may be positioned so that thedrive of the shaft 89 may be discontinued by shifting the hey in eitherdirection out of engagement .vith any one of the gears 83.

rEhe shaft V39, being thus driven by any one of the pairs of gears 3'?and S3, serves to drive the vvork table G in the following manner. Ithas fined thereto at its rear end a pinion 94; which meshes With pinion95 carried by the horizontal shaft 96 which drives the worm 9T throughthe coupling 98. The Worm gear 99 is carried on a vertical shaft 100 andis driven from the Worm 9'?. The pinion 11 (Fig. 4) being mounted uponthe vertical shaft 100 will be rotated in either direction and throughits engagement with the raclr 10 will reciprocate the table G at a speedwhich is controlled by the rotation of the cone pulley 441- and thechange speed gears which are selectively related.

The rod 90 (Figs. 7, 3 and projects forivardly beyond the end of thehollow shaft and this projecting end has a rack portion 101 formed byclosely spaced. parallel. circumferential grooves, the rack portionbeingl engagedby a pinion 102 by means of which the rod carrying the hey91 may be shifted longitudinally. rThe shaft 104e and sleeve 103 aresupported on the frame of the machine by a housing 103. The pinion 102is fined to a sleeve 103 which is loose on the transverse hand Wheelshaft 1021 and this sleeve has an arm 140 formed integral at the outerend thereof handle 111 is provided therewith by means of Which it may beturned to shift the key rod 90 to engage any desired gear 83 with theshaft S9 to obtain the desired rate of feed of the table G, or to shiftthe hey rod 90 to a neutral position with key 91 under Washers 93 andthus disconnect the power operated mechanism from the shaft 89. rJheoperation that has just been described relates to the means for driving`the table G from the motor at desir-ed speed.

1 also provide mechanism so that the table plurality of spaced G can bereciprocated by hand from each end of the machine as may be desired, sothat the operator can stand adjacent either of the grinding Wheels andmanually feed the Work. ln this connection l also provide associatedmeans located and arranged so that the driving connection of the gears88 with the shaft S9 can be shifted from either end of the machine, intoor out of operative engagement. rlie shaft 89 is provided at its outerend with a pinion 105 which mesh With a 106 carried by a countershaft-107 mounten in a bearing bracket 108. A bevel gear 109 is carried by theother end of the coun ershaft and meshes With the bevel gear 110 securedto the shaft 101. The shaft 96 is also provided with a gear 111 whichmeshes vrith pinion 112 secured to a countershaft 113, and a. beveledgear 111 is secured to Jthe outer end of such shaft. A. shaft 115similar to and extending parallel with the shaft 101 is loosely mountedin a sleeve 116 which is rotatably carried by the bearing 11.7 securedadjacent the end of the machine removed from the shaft 101. rIlle handWheels 15 are secured to one end of each of the shafts 1041 and 115which project from the front Wall of the machine frame adjacent eachgrinder and gears 1217 and 110, are carried by the other end of suchshafts and mesh with gears 11e and 109, respectively. A collar 11S isloosely mounted on the sleeve 11G and a lever 119 is secured thereto foractuating connecting link 120 which extends across the front of themachine and is pivotally secured at 121 to the collar 113. The other eneof the link 120 is pivotally secured at 122 tothe collar 123 Which ismounted upon the sleeve 103.

The collar 123` (Fig. 9) is loosely mounted upon the sleeve 103, and isprovided vrith an abutment member 112 (Figs. 1 and 9) which is securedtherewith and extends from the exterior thereof. The housing 103 isprovided With a pair of spa-ced laterally extending stops 141-3 betweenwhich the abutment member 14.2 can move a limited degree relative to thesleeve 103. A quadrant 141 is formed integral. with the collar 123 andextends adjacent the handle 111 exteriorly of the gear housing, and isprovided with a detents 145 with which the pin 116 carried by the handle111 can engage to retain the collar and sleeve together. The spring 1117Within the handle exerts only a slight pressure Which can easily beovercome by the operator. The detenta are arranged to receive the pin116 when the sleeve is rotated into the various positions necessary tocause the key 91 to engage with the several gears S8.

By shifting the key 91 relative to the gears S3, the work table can bedriven from the motor at different speeds. The hey 91 is carried by theshaft 907 and the rotation of the gear 102 with the rack 101 Will shiftthe shaft to position the key as desired. The gear 102 is keyed to thesleeve 103 and by rotating the sleeve through the handle 141 the key canbe moved. VJ hen the key rides on the v*ushers 93 the gears 33 will beinneutral, disconnecting the motor driven mechanism from the tablereciprocating gear mechanism.

Rotation of the collar 123 is limited by the abutment 142 coming incontactr witn either one of the stops 143. Sufficient rotation isprovided however to permit the sleeve 103 to rotate sui'liciently tomove the key 91 either into or out of engagement with one of the fears33, depending on the direction of rotation. 1t is desirable that the key91 take either an engaged or a disengaged position with no intermediateposition, and to this end a pin 143 (Figs. 1 and 9) seated against thespring 149 in the socket 150 is arranged to press on the roundedabutment 142 and direct it against either one of the stops 143. 1t willbe noted that the angular spacing between the detents 145 corresponds tothe distai'ice apart of the center lines of the gears 33 on the shaft89, while the angular space between the stops 143 corresponds toone-half of this distance, and it will be evident that no matter whichdetent 145 is engaged by the pin 140 the key 91 can be engaged ordisengaged by rotating `the collar 123 through the angular distancebetween the stops 143. The collars `123 and 118 being linked together bythe rod 120, rotation of either handle 141 or 119 will cause the key 91to shift its position either into or out of engagement with gears 83. Byoperating either of the handles 141 or 119, the key can be shifted toconnect a pair of gears that the table will be motor driven, or thegears can be disconnected to permit manual driving of the table. Whenthe gears 88 and the shaft 89 are disconnected, the table can hereciprocated by manually rotating the wheels 16 at either end of themachine, rllhus it will be seen that the operator can stand adjacenteither grinding wheel andk cause the table drive mechanism to move intoneutral or driving relation, and can from such position manually operatethe driving mechanism` but if it is desired to change the speed of tabletravel, it is necessary to operate the handle 141, moving it to adifferent position on the quadrant 144. n

lith the automatically operated mechanism referred to, 1 have providedmeans for changing the ratios of the speeds of thetable travel andspindle movements to suit the grinding machine to obtain the bestresults under various conditions. Such change of' the rat-io of speedisof course independent of the relationship between the table travel andthe bodily movement of the spindle, wherein the latter increases ordecreases in speed when the former increases or decreases in speed. Thislatter relationship arises from the arrangement whereby the mechanismcausing thebodily orbital movement of the spindle and the mechanism forcausing longitudinal movement of the table are driven from the same conepulley, and the rate of rotation of the cone pulley may be varied within:relatively small amounts over a relatively wide range by the operatorby means of the belt shifting mechanism associated with the cone pulleymechanism as previously explained. y

l also provide additional mechanism for transmitting power from themotor to the reverse gear mechanism for operating the table G, in whichthe drive is directly from the motor and not associated with the spindledrive, as previously described. A Ipulley 130 is secured upon thecountershaft 73, intermediate the pulleys 72 and 75, and a clutch 131 isassociated with the pulleys 72 and 130 to disengage both pulleys or toengage either of such pulleys with the shaft 73. The clutch 131 isoperated by meansfof either of two levers 131, one adjacent each head,which are connected by a link 131" to which a-shifter lever 131cconnected. 1n this manner either one of the pulleys 72 or 130 can beselectively engaged to drive the countershaft 73, or they can be bothdisengaged. A pulley 132 is secured upon the shaft 34 and a belt 133 eX-tends around the pulleys 132 and 130. When the clutch 131 is operated tocause the pulley 130 to rotate with the shaft 73, the power will betransmitted thereto from the countershaft 34 by the belt 133, whichshaft 34 is driven directly from the main drive shaft 23 by the belt 33.The table driving mechanism is operated from the countershaft 73 whichmay be selectively driven direc-tly from the main shaft 23 at a constantfast speed, or from the shaft 40 at a slower variable speed.

By this arrangement it will be seen that the table may be drivenrelatively rapidly by power from the shaft. 23 to bring the work intoapproxin'iate grinding position quickly. After the work has reached thisposition, the clutch 131 may be shifted either into neutral, or intorapid or slow table feed. When the clutch 131 engages the pulley 72 'iththe shaft 73, the pulley 130 is released from the shaft and the table isdriven from the cone' pulley, and the speed th'ineforeA is in a definiteratio with the orbitalmovement of the grinder spindles which are alsodriven from the cone pulleys. Vhen the clutch 131 engages the pulley 30,the table is driven rapidly directly from the shaft 34 which receivesits power from shaft 23 without driving through thecone pulleys. e

In Fig. 2 there is indicated a forcel feed lubrication system. A rotarypump 160 has its suction side connected by a pipe 161 to a lubricantreservoir H52. A liltering chamber 163 cont ing suitable lilteringscreens (not shown) receives overflow oil trom various parts ot themachine and discharges it into the reservoir 152. To the discharge sideoi" the pump i60 a pipe 1de leads to a head Ar 165 which distributes oilto the various parts ot the machine. The pump 160 has a shalt 166 onrwhich a pulley167 is mounted. A belt i6?) transmits power from pulley169 located on shaft Sel to pulley 167 which operates the pump 160.

lilith the mechani: i described it Will be seen that two grinders can berotated about their axis and also bodily in an orbital path about suchaxis, that the table can be reciprocated by a direct drive independentlyot the rotation ol tl e spindles, or in a detinite speed relation withthe orbital rotation oftA the spindles. lt will also be seen that thetable can be disconnected `from the power drive and that it can b-emanually ted from adjacent each grinder through a part or the samemechanism employed where it driven automatically.

lt is to be understood that the particular 'forms ot apparatus shown anddescribed, and the particular procedure set forth, are presented forpurposes ot explanation and illustration and `that various modilicationsof said apparatus and procedure can be made Without departing' from myinvention as delined in the appended claims.

What l claim is:

1. In a grinning machine of the character described, a pair ofoppositely disposed grinding Wheel spindles, mechanism for rotating saidspindles about their axes and orbitally about axes eccentric to saidspindles, a ivorlr feeding table reciprocable intermediate saidspindles, vmechanism for reciprocating said table, and common variablespeed mechanism tor actuating the table reciprocating mechanism and themechanism for causing orbital movement of the spindles at constant speedratio.

2. In a grinding machine ot the character described, a pair ofoppositely disposed grinding Wheel spindles, mechanism 'for rotatingsaid spindles axially, mechanism for rotating said spindles orbitally atvariable speeds about axes eccentric tothe spindles, a ivorlr feedingtable reciprocable between said spindles, mechanism including changespeed gearing for reciprocating said table, and means for selectivelyactuating said table reciprocating mechanism from either ot said orbitalrotating mechanisms and at a delinite speed ratio therewith.

3. ln a grinding` machine oi the character described, a pair ofoppositely disposed grinding Wheel spindles, mechanism for rotating saidspindles axially, mechanism for rotating said spindles in orbital pathsat variable speeds, a table reciprocable between said spindles,mechanism including change speed gearing for reciprocating said table,common means for driving said table feeding and said orbital rotatingmechanisms, and means for selectively connecting or disconnecting saidtable reciprocating mechanism and both of said spindle rotatingmechanisms from said common driving means.

e. ln a grinding machine of the character described, a pair ot'oppositely disposed grinding Wheel spindles, separate mechanisms forrotating said spindles axially, and orbitally about axes eccentric tothe spindles, a Worl; feeding table reciprocable between said spindles,mechanism for reciprocating'said table, means tor actuating said orbitalspindle rotating mechanisms, means for actuating said axial spindlerotating mechanisms, and means for selectively connecting said tablereciprocating mechanism with either of the said orital actuating means.

5. ln a grinding machine of the character described, a pair or'oppositely disposed grinding Wheel spindles, separate mechanisms torrotating said spindles axially, and orbitally about axes eccentric tosaid spindles, a ivorlr feeding table reciproca-ble intermediate saidspindles, mechanism for reciprocating said table, common actuating meansfor reciprocating said table mechanism and said mechanism for causingorbital rotation oi the spindles, means for disconnecting said tablereciprocating mechanism from said common actuating means, and drivingmeans tor causing rapid reciprocation of said table when disconnectedYfrom said common actuating means, whereby the Work may be rapidlyadjusted to grinding position, said last named means being independentoit the spindle actuation.

G. In a grinding machine of the character described, a pair ofoppositely disposed grinding Wheel spindles, a Worlr feeding tablereciprocable between said spindles, a main drive shaft connected with asource of power, a counter shaft driven trom said main drive shaft, apair of frictionally associated cone pulleys driven from said countershaft, mechanism operatively connected with one ot said pulleys forrotating said spindles in an orbital path, mechanism including reverseand change speed gearing driven from said cone pulleys for reciprocatingsaid table, a second means for driving said table reciprocatingmechanism trom said counter shaft, and mechanism for selectivelyconnecting or disconnecting either ot said means for driving said tablereciprocating mechanism.

7. ln a grinding machine of the character described, a pair ofoppositely disposed grinding Wheel spindles, a Work feeding tablereciprocable intermediate said spindles, poiver operated mechanism forrotating said spindles about their axes and in orbital paths about axeseccentric to the spindles, means l0- cated at each end of the machinefor rconnccting and disconnecting the power opera ted mechanisms forsaid table, and manually operable means for actuating said table.

8. ln a grinding machine ot' the character described, a pair otoppositely disposed grinding wheel spindles, a work feeding tablereciprocable between said spindles, power driven mechanism for rotatingsaid spindles, power driven mechanism including reverse and change speedgearing tor reciprocating said table, a pair of manually operativerotatable shatts geared to said reciprocating mechanism for actuatingthe same when said change speed gears are in neutral., and manuallyoperative .means tor placing said change speed gears into or out ofdriving relation, said means being actuable from adjacent either of saidmanually operative shafts.

9. ln a grindingr machine, in combination, a base, a pair of oppositelydisposed headstocks mounted on said base, a pair otl grinding wheelspindles carried by said headstocks, each said spindle extending towardthe opposed headstock and being rotatable about its own axis, andorbitally at variable speeds about an axis eccentric to its own, meanstor rotating each said spindle about its own axis at a relatively highspeed, a reciprocable work supporting table intermediate saidheadstocks, common driving means for rotating said grinding wheelspindles orbitally and tor reciprocating said work supporting tablebetween said headstocks at a definite speed ratio relative to the rateoit orbital movement of said spindle, whereby the relative movementbetween grinding wheels on said spindles and work mounted on said tablemay be controlled to give advantageous grinding results.

l0. In a grinding machine, in combination, a base, a pair of oppositelydisposed headstocks mounted on said base, a pair of grinding wheelspindles carried by said headstocks, each said spindle extending' towardthe opposed headstock and being rotatable about its own exif andorbitally at variable speeds about an axis eccentric to its own, meansvfor rotating each said spindle about its own axis at a relatively highspeed, a reciprocable work supporting table intermediate said headstcks, common driving means for rotating said grinding wheel spindlesorbitally and tor reciprocating said work supporting table between saidheadstocks at a definite speed ratio relative to the rate of orbitalmovement of said spindle whereby the relative movement between grindingwheels on said spindles and work mounted on said table may be controlledto give advantageous grinding results, and means for varying saiddefinite speed ratio oi table reciprocation to spindle orbital speedwhereby the most advantageous relative movement between grinding wheeland work may be had for the particular work in hand.

ll. In a grinding machine, in combination, a base, a pair olf oppositelydisposed headstocks mounted on said base, a pair of grinding wheelspindles carried by said headstocks, each said spindle extending towardthe opposed headstock and being rotatable about its own axis, andorbitally at variable speeds about an anis eccentric to its own, means:t'or rotating each said spindle about its own axis at a relatively highspeed, a reciprocable work supporting` table intermediate saidheadstocks, a common driving means for rotating said grinding wheelspindles orbitally and for reciprocating said work supporting tablebetween said headstocks/at a definite speed ratio relative to the rateot orbital movement ot said spindle whereby the relative movementbetween gril'iding wheels on said spindles and work mounted on saidtable may be controlled to give advantageous grinding results, andselectively operated means for rcciprocating said table independentlyof. said spindle orbital movement and at a relatively high speed wherebypositioningof the work relative to the grinding wheel spindles may bemickly accomplished.

l2. In a grinding machine, in combination, a base, a pair ot' oppositelydisposed headstoeks mounted on said base, a pair of grinding wheelspindles carried by said headstocks, each said spindle extending' towardthe opposed headstock and being rotatable about its own axis, andorbitally at variable speeds about an axis eccentric to its own, means'tor rotating each said spindle about its own axis at a relatively highspeed, a reciprocable work supporting table intermediate saidheadstocks, common driving means for rotating said grinding wheelspindles orbitally and for reciprocating said work supporting tablebetween said headstocks at a definite speed ratio relative to the rateof orbital movement of said spindle whereby the relative movenientbetween the grinding wheels on said spindles and work mounted on saidtable may be controlled to give advantageous grinding results, and meansfor reciprocating said table manually independently oit said spindleorbital movement whereby adjustments of' the `grinding machine relativeto the work and vice versa readily may be made.

13. In a grinding machine, in combination, a base, a pair of oppositelydisposed headstocks mounted on said base, a pair of grind.- ing wheelspindles carried by said headstocks, each said spindle extending towardthe opposed headstock and being rotatable about its own axis, andorbitally at variable speeds about an axis eccentric to its own, meansfor rotating each said spindle about its own axis at a relatively highspeed, a reciprocable work supporting table intermediate saidheadstocks, common driving means for rotating said grinding wheelspindles orbit-ally and for reciprocating said work supporting tablebetween said headstocls at a definite speed ratio relative to the rateof orbital movement ot said spindle whereby the relative movementbetween the grinding Wheels on said spindles and Worlr mounted on saidtable may be controlled to give advantageous grinding results,selectively operated means for recip roc-ating said table independentlyof said spindle orbital movement and at a relatively high speed, andmeans or'reoiprocat-ing said table manually independently7 of saidspindle orbital movement whereby adjustments of the grinding machinerelative to the Work and vice versa readily may be made.

14. In a grinding machine, in combination.,

4a base, pair ot spaced oppositely disposed headstocls mounted on saidbase, a pair o grinding Wheel spindles carried by said headstoclrs, eachsaid spindle extending toward the opposed headstock and being rotatableabout its own axis, and orbitally about an axis eccentric to its ovvn,means for selectively or Vabout its own axis simultaneously rotatingeach said spindle at a relatively high speed, a reciprocable Worksupport-ing table intermediate said headstoclrs, common driving meansfor rotating said grinding Wheel spindles orbita-ily at variable ratesof speed and for reciprocating said Work supporting` table intermediatesaid headstoclis always at a deiinite speed ratio rela ve to the rate oforbital movement of said spindle, whereby the reciprocative speed ofsaid table may be maintained at a definite ratio to the orbital speed ofsaid spindles regardless ot the particular orbital speed of saidspindles, means for varying said definite speed ratio of tablereciprocation relative to spindle orbital speed, selectively operatedmeans for reciprocating said table a speed independent of said spindleorbital speed, and means for reciprocating' said table manually, wherebyadjustments of the grinding machine relative to the Work, and viceversa, readily may be made.

In testimony Whereot l ali-ix my signature.

VHLLIAM J. BAUMBERGER.

CERTIFICATE OF CORRECTION.

Patent No. 1,730,838. Granted October 8, 1929, to

WILLIAM J. BAUMBERGER.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 92, for the figure "32" read "32"'; page 6 lines 94 and 9S, claim5, strike lout the word "reciprocating" and insert the same to followafter the word "table" in line 95, same claim; and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record oi the case in the Patent Office.

Signed and sealed this 12th day of November, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

